1. Field of the Invention
The present invention relates to an apparatus and method for inspecting electrical characteristics, such as open/short, with regard to the electrode patterns formed on a panel type product such as a PDP(Plasma Display Panel).
2. Description of the Background Art
Generally, a glass panel, for example, a PDP, as shown in FIGS. 1a and 1b, comprises a front panel 10 and a rear panel 11. A large number of electrode patterns 10a and 11a are formed on the surfaces of the front and rear panels 10 and 11.
In a 42 inch PDP, a line width and a pitch of one among electrode patterns 10a and 10b are 50 xcexcm and 30 xcexcm, respectively, whereas since a line length is 1 m long following cases that the line is cut, an open state, or connected with an adjacent line, a short state, are frequently occurred not only in a process for forming an electrode pattern and but also in a manufacturing process such as a heating process being repeated thereafter. Accordingly, an inspection process that whether the formed electrode pattern become opened/shorted or not, in the middle of the manufacturing process, is requisite for increase of yield of the PDP manufacturing processes.
As mentioned above, as shown in FIG. 2, a test pin block 12 is used in order to inspect electrical characteristics of the electrode patterns 10a and 11a in a conventional art. When inspecting by using the test pin, a large number of pins 12a formed at the test pin block 12 are contacted to connector connection portions, that is, both ends 10b and 10c of the electrode pattern 10a or both ends 11b and 11c of the electrode pattern 11a and thereafter a continuity test is performed between an inspection object electrode pattern and an adjacent pattern, and then electrical characteristics of the corresponding pattern, that is, the existence of open or short, is inspected.
However, the above inspection method has several disadvantages as follows.
First, the test pin block 12 of FIG. 3 is expendables with a high price and has no durability and so it becomes a factor for raising the cost price of goods. That is, an inspection by the test pin block 12 is a pressure contact type and so the test pin is damaged easily.
Second, in a case that a model or a design of goods is changed, since a position and a pitch etc. of the electrode pattern is changed, the conventional test pin block 12 and the related mechanical parts all must be replaced. Accordingly, since there is no flexibility against the change of the model or the design of goods, the conventional inspection method cannot be used in flexible manner.
Third, in a case that the electrode patterns are formed in those ways as shown in FIGS. 1a and 1b, since, when inspecting, the pin 12a of the test pin block 12 must be contacted to pixel portions xe2x80x9cAxe2x80x9d and xe2x80x9cBxe2x80x9d besides a connector connection portion of a PDP pattern, there is a disadvantage that an another defective factor is generated by scratching according to the contact.
Fourth, in a case that flatness of a glass panel on which electrode patterns are formed is not good, since the pin 12a of the test pin block 12 can exactly be contacted to the electrode patterns, the whole of the glass panel must be fixed by a separate accurate large vacuum chuck and an accurate servo mechanism of x-y-xcex8 of three axis is required in order to set an accurate x-y positioning of the electrode patterns and resultantly these become factors to raise the cost in manufacturing.
Accordingly, it is a first object of the present invention to provide an inspection apparatus and method adapted to a scanning technique employing a rolling wire probe, in order to solve the above problems, in which it can be used flexibly up to electrode patterns having various forms and a factor generating scratch become reduced and a burden of the cost rising in manufacturing become decreased.
It is a second object of the present invention to provide an inspection apparatus and method adapted to a scanning technique employing a rolling wire probe in which an accuracy of inspection can be enhanced and expandable parts can be replaced efficiently.
In order to achieve the above-described object of one aspect of the present invention, in an inspection of electrical characteristics of the plural number of electrode patterns formed on a panel, the apparatus comprises a rolling wire probe having a rolling wire rotating at a constant speed in order to be performed a rolling contact sliplessly across the electrode patterns; a control unit for controlling operations of the inspection apparatus wholly and discriminating the electrical characteristics according to the electrical signal sensed through the rolling wire provided to the rolling wire probe.